Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are

enchytraeid Enchytraeidae is a family of microdrile oligochaetes. They resemble small earthworms and include both terrestrial species known as potworms that live in highly organic terrestrial environments, as well as some that are marine. The peculiar genus ...

annelids The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to vario ...

of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Mesenchytraeus''. The majority of the

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

in the genus are abundant in gravel beds or the banks of

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

ine habitats, but the best-known members of the genus are found in

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

ice. They include the only annelid worms known to spend their entire lives in

ice, and some of the few

metazoan Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a ho ...

s to complete their entire life cycle at conditions below . They were discovered in a wide range of environments, which include level snowfields, steep avalanche cones, crevasse walls, glacial rivers and pools, and hard glacier ice. These organisms are unique in that they can simply move between tightly packed ice crystals. They utilize setae, which are small bristles found on the outside of their bodies, to grip the ice and pull themselves along. Ice Worm against Fingernail

The genus contains 77

, including the North American glacier ice worm (''

Mesenchytraeus solifugus ''Mesenchytraeus solifugus'', commonly called an ice worm, is a species of Oligochaeta, oligochaete worm that inhabits coastal glaciers in northwestern North America. ''M. solifugus'' is dark brown and grows to about 15 mm long and 0.5&nb ...

'') and the Yosemite snow worm (''

Mesenchytraeus gelidus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

''). Ice worms eat snow algae and bacteria. The specimens researched by Scott Hotaling, researcher at

Washington State University Washington State University (WSU, or colloquially Wazzu) is a Public university, public Land-grant university, land-grant research university in Pullman, Washington, United States. Founded in 1890, WSU is also one of the oldest Land-grant uni ...

, live at zero degrees Celsius (32 degrees Fahrenheit) and die if temperatures dip even slightly below that.

History

In North America, the first ice worms

were discovered in 1887 in

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

, on the

Muir Glacier Muir Glacier is a glacier in Glacier Bay National Park and Preserve in the U.S. state of Alaska. It is currently about wide at the terminus. As recently as the mid-1980s the glacier was a tidewater glacier and calved icebergs from a wall of ...

. These glacier ice worms can be found on glaciers in Alaska,

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

and

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

. They have not been found in other glaciated regions of the world.

Description

The specific name ''solifugus'' for the North American species, ''

'', is Latin for "sun-avoiding," as ice worms retreat underneath the ice before dawn.

Enzymes An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as pro ...

in ice worms have very low optimal temperatures, and can be denatured at even a few degrees above . When ice worms are exposed to temperatures as modest as , their membrane structures disassociate and fall apart (i.e., "melt") causing the worm itself to "liquefy." Ice worms are several centimeters long, and can be black, blue, or white. They come to the surface of the glaciers in the evening and morning. On

Suiattle Glacier Suiattle Glacier is located in the Glacier Peak Wilderness in the U.S. state of Washington. The glacier is within Mount Baker-Snoqualmie National Forest and nearly touches Honeycomb and White River glaciers separated from them by an arête off t ...

in the

North Cascades The North Cascades are a section of the Cascade Range of western North America. They span the border between the Provinces and territories of Canada, Canadian province of British Columbia and the U.S. state of Washington (state), Washington and ...

, population counts indicated over 7 billion ice worms. It is not known how ice worms tunnel through the ice. Some scientists believe they travel through microscopic fissures in ice sheets, while others believe they secrete some chemical which can melt ice by lowering its freezing point, like an

antifreeze An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments. Common antifreezes also increase the boiling point of the liquid, allow ...

. They feed on snow algae.

Species

The genus contains 77

. They are the following: *''

Mesenchytraeus affinis Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Michaelsen, 1901 *''

Mesenchytraeus altus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Welch, 1917 *''

Mesenchytraeus americanus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Bell, 1942 *''

Mesenchytraeus anisodiverticulus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Shen, Chen & Xie, 2012 *''

Mesenchytraeus antaeus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Rota & Brinkhurst, 2000 *''

Mesenchytraeus arcticus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Bell, 1962 *''

Mesenchytraeus argentatus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine h ...

'' Welch, 1916 *'' Mesenchytraeus gigachaetus'' Xie, 2012 *'' Mesenchytraeus glandulosus'' (Levinsen, 1884) *'' Mesenchytraeus grandis'' Eisen, 1904 *'' Mesenchytraeus grebnitzkyi'' Michaelsen, 1901 *'' Mesenchytraeus groenlandicus'' Nielsen & Christensen, 1959 *'' Mesenchytraeus hamiltoni'' Healy, 1996b *'' Mesenchytraeus harrimani'' Eisen, 1904 *'' Mesenchytraeus hydrius'' Welch, 1919a *'' Mesenchytraeus johanseni'' Welch, 1919b *'' Mesenchytraeus kincaidi'' Eisen, 1904 *'' Mesenchytraeus kontrimavichusi'' Piper, MacLean & Christensen, 1982 *'' Mesenchytraeus konyamensis'' Michaelsen, 1916 *'' Mesenchytraeus kuehnelti'' Dózsa-Farkas, 1991a *'' Mesenchytraeus kuril'' Healy & Timm, 2000 *'' Mesenchytraeus lusitanicus'' Collado, Martínez-Ansemil, and Giani, 1993 *'' Mesenchytraeus macnabi'' Bell, 1942 *'' Mesenchytraeus maculatus'' Eisen, 1904 *'' Mesenchytraeus magnus'' Altman, 1936 *'' Mesenchytraeus melanocephalus'' Christensen & Dózsa-Farkas, 1999 *'' Mesenchytraeus minimus'' Altman, 1936 *'' Mesenchytraeus mirabilis'' Eisen, 1878 *'' Mesenchytraeus monochaetus'' Bretscher, 1900 *'' Mesenchytraeus monodiverticulus'' Shen, Chen & Xie, 2012 *'' Mesenchytraeus monothecatus'' Bell, 1945 *'' Mesenchytraeus multispinus'' (Grube, 1851) *'' Mesenchytraeus nanus'' Eisen, 1904 *'' Mesenchytraeus obscurus'' Eisen, 1904 *'' Mesenchytraeus ogloblini'' Černosvitov, 1928b *'' Mesenchytraeus orcae'' Eisen, 1904 *'' Mesenchytraeus pedatus'' Eisen, 1904 *'' Mesenchytraeus pelicensis'' Issel, 1905c *'' Mesenchytraeus penicillus'' Eisen, 1904 *''

Mesenchytraeus primaevus Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine ...

'' Eisen, 1878 *'' Mesenchytraeus rhithralis'' Healy & Fend, 2002 *'' Mesenchytraeus sanguineus'' Nielsen & Christensen, 1959 *'' Mesenchytraeus setchelli'' Eisen, 1904 *''

'' (Emery, 1898) :*'' Mesenchytraeus solifugus solifugus'' (Emery, 1898) :*'' Mesenchytraeus solifugus rainierensis'' Welch, 1916 *'' Mesenchytraeus straminicolus'' Rota, 1995 *'' Mesenchytraeus sveni'' Christensen & Dózsa-Farkas, 1999 *'' Mesenchytraeus svetae'' Piper, MacLean & Christensen, 1982 *'' Mesenchytraeus tetrapodus'' Timm, 1978 *'' Mesenchytraeus torbeni'' Christensen & Dózsa-Farkas, 1999 *'' Mesenchytraeus tundrus'' Piper, MacLean & Christensen, 1982 *'' Mesenchytraeus unalaskae'' Eisen, 1904 *'' Mesenchytraeus variabilis'' Cejka, 1914 *'' Mesenchytraeus vegae'' Eisen, 1904 *'' Mesenchytraeus viivi'' Timm, 1978 *'' Mesenchytraeus vshivkovae'' Timm, 1994 ''Mesenchytraeus franzi'' is a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of '' Cognettia clarae''. ''Mesenchytraeus megachaetae'' Shen, Chen & Xie, 2011 has been renamed ''Mesenchytraeus gigachaetus'' Xie, 2012 due to the previous name being preoccupied by ''Mesenchytraeus megachaetae'' Bretscher, 1901, a junior synonym of '' Mesenchytraeus armatus.''

References

External links

Seattle Times Article on Iceworms
{{Taxonbar, from=Q656119 Enchytraeidae